Many mobile citizens band antennas currently in use are comprised of a mounting means capable of being temporarily affixed to a surface on a vehicle and a base loaded vertical antenna having a threaded interconnection so that the antenna can be detached from the mounting means. This type of antenna has found favor among the public because it can be easily dismounted from a vehicle and stowed out of sight. The dismounting procedure can be accomplished in two ways. With many mobile antenna mounts, the mount itself is easily disengaged and can be repeatedly removed and reattached. With other types, the mount is more permanently attached and the antenna is simply unscrewed from the mount for stowage. The antennas supplied with these mounts have in the past been base loaded antennas. Base loaded antennas are comprised of a vertical flexible conducting rod and an integral loading coil in a housing at the base of the rod. The coil housing normally has a threaded socket which screws onto a male threaded stud on the mount so as to connect the antenna to the mount both mechanically and electrically. These studs ordinarily have a 5/8.times.20 thread.
Upper loaded antennas, that is to say a vertical flexible conducting rod having a loading coil intermediate its ends, have also been used with mobile citizens band antenna systems.
Loading coils are employed to increase the effective electrical length of the antenna beyond its physical length so that the antenna presents a low impedance to the transmission line feeding it and the transmission line can energize the antenna with a minimum standing wave ratio. Upper loaded antennas normally have male threads on their lower extremity and are screwed into a threaded socket in an associated mount.
Thus heretofore if one purchased a base loaded antenna and mount he was precluded from using a more efficiently radiating upper loaded antenna with his mount because of the different threading arrangement of the two types of antennas and mounts. Interconnection between an antenna of one type and the mounting means of another type was impossible.